1. Field of the Invention
This invention relates generally to an industrial process, and, more particularly, to performing fault detection in parallel in a semiconductor fabrication process.
2. Description of the Related Art
There is a constant drive within the semiconductor industry to increase the quality, reliability and throughput of integrated circuit devices, e.g., microprocessors, memory devices, and the like. This drive is fueled by consumer demands for higher quality computers and electronic devices that operate more reliably. These demands have resulted in a continual improvement in the manufacture of semiconductor devices, e.g., transistors, as well as in the manufacture of integrated circuit devices incorporating such transistors. Additionally, reducing the defects in the manufacture of the components of a typical transistor also lowers the overall cost per transistor as well as the cost of integrated circuit devices incorporating such transistors.
Generally, a set of processing steps is performed on a group of wafers, sometimes referred to as a “lot,” using a variety of processing tools, including photolithography steppers, etch tools, deposition tools, polishing tools, rapid thermal processing tools, implantation tools, etc. The technologies underlying semiconductor processing tools have attracted increased attention over the last several years, resulting in substantial improvements.
One technique for improving the operation of a semiconductor processing line includes using a factory wide control system to automatically control the operation of the various processing tools. The manufacturing tools communicate with a manufacturing framework or a network of processing modules. Each manufacturing tool is generally connected to an equipment interface. The equipment interface is connected to a machine interface, which facilitates communications between the manufacturing tool and the manufacturing framework. The machine interface can generally be part of an Advanced Process Control (APC) system. The APC system initiates a control script based upon a manufacturing model, which can be a software program that automatically retrieves the data needed to execute a manufacturing process. Often, semiconductor devices are staged through multiple manufacturing tools for multiple processes, generating data relating to the quality of the processed semiconductor devices.
During the fabrication process, various events may take place that affect the performance of the devices being fabricated. That is, variations in the fabrication process steps result in device performance variations. Factors, such as feature critical dimensions, doping levels, particle contamination, film optical properties, film thickness, film uniformity, etc., all may potentially affect the end performance of the device. Various tools in the processing line are controlled in accordance with performance models to reduce processing variation. Commonly controlled tools include photolithography steppers, polishing tools, etching tools, and deposition tools. Pre-processing and/or post-processing metrology data is supplied to process controllers for the tools. Operating recipe parameters, such as processing time, are calculated by the process controllers based on the performance model and the metrology data to attempt to achieve post-processing results as close to a target value as possible. Reducing variation in this manner leads to increased throughput, reduced cost, higher device performance, etc., all of which equate to increased profitability.
Fault detection can also affect the profitability of industrial processes, including semiconductor manufacturing processes. Typically, a fault model representative of the operation of a processing tool may be utilized to detect faults. A fault model, which may be generated based on historical data, can range from a small, simple model to a large, more complex model, depending on the particular implementation. Each processing tool commonly has its own associated fault model to detect faults associated with that processing tool. As the number of processing tools increases in a manufacturing system, the number of fault models required also increases, which may increase the hardware resources needed to store the fault models. Furthermore, substantial human and hardware resources may be expended to keep the large number of fault models regularly updated.
The present invention is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.